I just did that to my '87 syncro weekender.  look on the samba.com site I
saw a set there.

>From: Andy Frank <andyfrank@CCCACCESS.ORG>
>Reply-To: Andy Frank <andyfrank@CCCACCESS.ORG>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Swivel seat
>Date: Sun, 14 Jan 2007 14:02:59 -0800
>
>I have a 1990 Weekender.  I'd like to convert the passenger seat into
>a swivel seat.  Can someone point me to a source to get the parts I
>need? Is it just a matter of searching junk yards, is there an
>after-market source, or is there someone out there who might have one for
>sale?
>
>I'm new to the list so forgive me if this has been gone over in the
>past.  I searched through the archives but I didn't find anything too
>recent (at least with the search words I chose).
>
>Andy